6 magical ways breast milk changes to meet your baby’s needs

August 01 2018

Is it any wonder human breast milk has been called ‘liquid gold’?

This magic potion made by mothers is a living fluid that changes depending on the needs of your baby. It can seal your newborn’s gut against potentially harmful bacteria, viruses and allergens. It can boost your growing baby’s immunity by producing antibodies to bugs your baby is exposed to. And it can change in composition depending on whether your baby is hungry, thirsty, or going through a growth spurt.

The composition of breast milk and nutrients, including macronutrients, and immune factor concentrations change according to the age and development of your baby, providing the perfect food for your baby as he grows from birth through starting family foods and becoming mobile to weaning.

For instance, studies show that the milk of mothers who have premature babies contained more calories, a greater fat concentration, more protein, sodium and sIgA (secretory immunoglobulin A) than the milk of newborn term mothers.

Often referred to as baby’s first immunisation, colostrum, the sticky yellowish first ‘milk’ will maintain your newborn’s blood sugar and kickstart important immunologic responses in your baby’s gut, influencing the development of normal gut flora, and preventing the growth of harmful bacteria. It also has a laxative effect that helps your newborn to pass meconium, that first black, tarry bowel motion. This reduces the reabsorption of bilirubin – a yellow pigment that occurs naturally when red blood cells partially break down – reducing the risks of jaundice.

For the next day or two as your milk making hormones are triggered by the expulsion of your placenta, and a drop in progesterone (one of your pregnancy hormones) your milk will ‘come in’. It will still be a yellowish colour and is now called ‘transitional milk’ – as it ‘transitions’ from colostrum to mature milk somewhere between three and five days after birth, although this can vary.

Although your mature breast milk no longer looks ‘creamy’ and can even appear ‘watery’, however long you breastfeed, your milk will not ‘lose its goodness’ – some immune factors actually become more concentrated during the second year of life, right when your baby becomes mobile enough to play with other children and is exposed to a greater array of bugs!

2. Breast milk changes during a feed

The fat content of your breast milk changes throughout a feed and your baby can regulate this by his sucking – as long as you allow your baby to feed as long and as often as he needs. When your baby is thirsty and begins to suck he will firstly get the more ‘watery’ foremilk to quench his thirst, as the feed goes on, he will stimulate your letdown reflex. As your milk ‘lets down’ this reflex will be squeezing the higher fat milk or ‘hind milk’ down to your baby to meet his energy needs. This doesn’t mean there are two types of milk: consider how, when you have a cold tap running and you turn on the hot tap, the water gradually mixes from cool to warm. This is a similar process as the higher fat milk is made available to your baby throughout the feed. This means that your baby can control the kind of milk he needs at each feed through the kind of sucking he uses, as well as how long he feeds.

3. Breast milk changes at night-time

Day and night milk have different components: studies by researchers in Spain have found higher levels of nucleotides (proteins) that stimulate GABA (Gamma-amino butyric acid), a sleep inducing neurotransmitter and melatonin. Evening breast milk is also rich in tryptophan, a sleep-inducing amino acid that is a precursor to serotonin as well as amino acids that promote serotonin synthesis. Serotonin is a vital hormone for brain function and development that makes the brain work better, supports a good mood and helps with sleep cycles. Recent studies conclude that ingestion of tryptophan in infancy leads to more serotonin development, so as long as your baby needs night feeds, be reassured, you are supporting his potential for life-long wellbeing.

4. Breast milk changes according to your diet

Although the nutrient stores you have laid down during pregnancy will mean that your milk is nutritious and balanced for all of your baby’s needs, there is evidence that some nutrients will be influenced by your own diet. For instance, the proportion of different fatty acids, some vitamins and elements such as selenium and iodine vary according to levels in your own diet. Further research has linked ratios of fatty acids in mother’s milk and her baby’s tendency to develop certain allergies. Other studies report that levels of omega three fatty acids in mothers’ diets are not only linked with healthy neural development and sleep patterns in babies as well as boosting the immunity-strengthening properties of breast milk.

5. The flavour of breast milk changes

It’s thought that exclusive breastfeeding could make your baby a less fussy eater when she starts eating family foods because the flavours of foods you eat will influence the taste of your breast milk. This in turn familiarizes your baby with these flavours. Studies show that babies love the taste of vanilla, garlic and cinnamon flavoured breast milk (when mothers eat foods with these flavours) so may empty your breasts more effectively, enhancing milk production.

6. Kissing your baby will change your breast milk

That irresistible urge to plant kisses all over your baby will also help to boost her immune system: when you kiss your baby, you are sampling the pathogens on her skin which are then transferred to your lymphatic system where you will produce antibodies to any bugs. These antibodies will then pass through your breast milk to your baby and boost her immune system.

This system works the same way whenever your baby is exposed to a bug, whether you have been exposed or your child has played with another child’s toy or been touched by a doting family member and come in contact with viruses or bacteria. The transfer of your baby’s saliva to your breasts will signal your immune system to make antibodies which are then transferred to your baby in your breast milk, protecting her against potential illness.

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Pinky McKay is Australia’s most recognised and respected Breastfeeding expert. She’s an IBCLC lactation consultant, best-selling author of ‘Sleeping Like a Baby’ and ‘Parenting by Heart’ (Penguin Random House) and creator of Boobie Bikkies, the original natural, organic cookies to nourish breastfeeding mothers and support a healthy breast milk supply.